Martian hills tell of the planet’s humid past

A team of scientists has explored a fairly large region in the northern part of Mars using images from several orbiters. They believe that the hills covered with a thick layer of clay are evidence of the presence of a sea in the past.

Martian hills. Source: www.space.com

Martian hills

It is most likely that several billion years ago, most of the Northern Hemisphere of Mars was covered by an ocean. The theory about this arose many years ago, and it is quite popular. No one is completely sure about it, but now scientists have a compelling new confirmation.

The researchers used HiRISE and CRISM cameras mounted on the Mars Reconnaissance Orbiter, as well as data from the Mars Express and ExoMars Trace Gas Orbiter spacecraft, to conduct geologic studies of the red planet’s surface. Their goal was Chryse Planitia.

Chryse Planitia is an area about the size of Great Britain that lies below the average Martian surface. Once there were mountains, but early in the red planet’s history a large body crashed there and now only hills remain. These are the ones that have been the object of the scientists’ research.

Results of the study

In total, scientists counted more than 15,000 hills and table mountains up to 500 meters high on Chryse Planitia. There are many similar landforms in other parts of Mars, as well as on Earth. We have them formed by water and wind, which erode the rocks.

This is what gave researchers the idea to analyze what the material of these hills represents. The result was unambiguous: clay. This extremely fine-grained sedimentary rock certainly cannot be formed without running water. Therefore, the conclusion is fairly expected: there was once a sea on Chryse Planitia.

At the same time, the scientists found that directly under the clay layer there are rocks. That is, the body of water only existed for a certain amount of time, from about 4.2 to 3.7 billion years ago, during the so-called Noah period of the planet’s history.

In general, Chryse Planitia is a rather famous region of Mars. The Viking 1 spacecraft landed there in 1976. And in a few years, the Rosalind Franklin rover is scheduled to begin operations nearby. Perhaps then all assumptions about the past of this place will finally be confirmed.

According to www.space.com

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